function fun() {
    window.onload = function(){
        var t1 = new Tab("div1");
        t1.init();
    }

    function Tab(id){
        this.oParent = document.getElementById(id);
        this.aInput = this.oParent.getElementsByTagName("input");
        this.aDiv = this.oParent.getElementsByTagName("div");
        this.iNow = 0;
    }

    Tab.prototype.init = function(){
        var This = this;
        for(var i=0; i<this.aInput.length;i++){
            this.aInput[i].index = i;
            this.aInput[i].onclick=function(){
                This.change(this);
            }
        }
    }
    Tab.prototype.change = function(obj){
        for(var i=0; i<this.aInput.length;i++){
            this.aInput[i].className="";
            this.aDiv[i].style.display="none";
        }
        obj.className="active";
        this.aDiv[obj.index].style.display="block";
    }
}
fun()